Purging apparatus and purging method

ABSTRACT

It is an object of the present invention to easily and securely perform the removal operation of contaminant or the like from a wafer housed in a FOUP. To achieve the object, a purging apparatus of the present invention removes contaminant or the like from a wafer by moving a gas supply nozzle along a direction in which wafers are superimposed at the front of an opening while a lid of the FOUP is separated from a body and spraying clean gas on each wafer from the gas supply nozzle.

TECHNICAL FIELD

The present invention relates to a product housing container used tohouse a product in a product manufacturing process in which the processof a semiconductor, panel for a flat panel display, optical disk, or thelike is performed in a high clean environment. More minutely, thepresent invention relates to a cleaning method of the inside of theso-called FOUP (front-opening unified pod) used in a process fortreating a semiconductor wafer mainly having a diameter of 300 mm as aproduct to be housed.

BACKGROUND ART

A process for fabricating a semiconductor device has dealt with theissue of cleanliness required in such processes by forming the wholeplant for applying various treatments to a wafer into a clean room.However, because the diameter of a wafer is increased, the above methodbecomes a problem in cost to obtain the high clean environment. Meansfor securing a mini-environment (very small environment) space keeping ahigh cleaning degree has been taken for various treating apparatuses inthese several years.

Specifically, instead of increasing the cleaning degree of the entirefactory, only insides of treating apparatuses and inside of a storingcontainer (hereafter referred to as pod) during movement between them ina manufacturing process are kept at a high cleaning degree. This pod isreferred to as FOUP as described above. Thus, by bringing a small spaceinto a high cleaning degree, the advantage same as the case of formingthe whole plant into a clean room is obtained, equipment investment andmaintenance cost are reduced, and an efficient production process isrealized.

A semiconductor treating apparatus or the like dealing with theso-called mini-environment system actually used is briefly describedbelow. FIG. 15 shows the whole of a semiconductor wafer treatingapparatus 50. The semiconductor wafer treating apparatus 50 is mainlyconstituted of a load port portion 51, a conveying chamber 52, andtreating chamber 59. Junctions therebetween are comparted by aload-port-side compartment 55 a and cover 58 a, andtreating-chamber-side compartment 55 b and cover 58 b. In the conveyingchamber 52 in the semiconductor wafer treating apparatus 50, todischarge dust and keep a high cleaning degree, an air flow is generatedfrom the upper portion toward the lower portion of the chamber 52 by afan (not illustrated) set on the chamber. Thus, dust is continuouslydischarged toward the lower side.

On the load port portion 51, a pod 2 serving as a container for storinga silicon wafer (hereafter referred to as wafer) or the like is set on apedestal 53. As previously described, the inside of the conveyingchamber 52 is kept at a high cleaning degree in order to treat a wafer 1and moreover, a robot arm 54 is set to the inside. This robot arm 54moves the wafer between the inside of the pod 2 and the inside of thetreating chamber 59. Various mechanisms for forming a thin film on thesurface of the wafer or the like and treating the thin film aregenerally included in the treating chamber 59 but description of theseconfigurations is omitted because they are not directly related to thepresent invention.

The pod 2 has a space for storing the wafer 1 which is a product to betreated at the inside and includes a boxy body portion 2 a having anopening on any face and a lid 4 for closing the opening. A shelf havinga plurality of stages for overlapping wafers 1 in one direction is setin the body portion 2 a and wafers 1 mounted on the stages are housed inthe pod 2 by making intervals between the wafers 1 constant. In the caseof the example shown here, the direction for overlapping the wafers 1 isvertical. An opening 10 is formed at the load port portion 51-side ofthe conveying chamber 52. The opening 10 is set to a position facing theopening of the pod 2 when the pod 2 is set on the load port portion 51so as to be close to the opening 10. An opener 3 to be described lateris also set nearby the opening 10 in the conveying chamber 52.

FIGS. 16A and 16B show a side sectional view obtained by enlarging theopener-3 portion in a conventional apparatus and a front view viewingthe opener 3 from the conveying chamber-52 side. FIG. 17 shows aschematic view of the side cross section of a state in which the lid 4is removed from the pod 2 by using the opener 3. The opener 3 has a door6 and a door arm 42. A fixed member 46 is set to the door 6 and the door6 is rotatably connected to one end of the door arm 42 through the fixedmember 46. The other end of the door arm 42 is supported to the frontend of a rod 37 which is a part of a pneumatic cylinder 31 rotatablythrough a pivot 40.

A through-hole is formed between one end of and the other end of thedoor arm 42. A fulcrum 41 is constituted by the fact that anot-illustrated pin passes through the through-hole and a hole of afixed portion 39 fixed to a support member 60 of a movable portion 56for vertically moving the opener 3. Therefore, the door arm 42 becomesrotatable about the fulcrum 41 in accordance with the telescopic motionof the rod 37 due to driving by the cylinder 31. The fulcrum 41 of thedoor arm 42 is fixed to the support member 60 set to the movable portion56 which can be vertically moved. The door 6 has holding ports 11 a and11 b and is able to hold the lid 4 of the pod 2 by means of vacuumattraction.

To treat the wafer 1 with these configurations, the pod 2 is set on thepedestal 53 so as to be close to the conveying-chamber opening 10 tohold the lid 4 by the door 6. Then, when contracting the rod of thecylinder 31, the door arm 42 moves so as to leave the conveying-chamberopening 10 about the fulcrum 41. The door 6 rotates together with thelid 4 to remove the lid 4 from the pod 2 in accordance with the aboveoperation. The state is shown in FIG. 17. Thereafter, the movableportion 56 is lowered to convey the lid 4 up to a predeterminedevacuation position.

The inside of the pod 2 while housing a wafer or the like is filled withdry nitrogen or the like controlled at a high cleaning degree to preventcontaminant, oxidizing gas or the like from entering the pod. However,because the pod also houses a wafer after passing through the treatingchamber, a case is considered in which contaminant or the like attachesto the wafer in the treating chamber or the like and this is broughtinto the pod. When the contaminant or the like is brought into the nexttreating chamber, a case may occur in which a desired wafer treatmentwhich should be originally performed may not be performed when passingthrough the treating chamber. Therefore, when moving the wafer from thepod to the conveying chamber, it is necessary to remove the contaminantor the like.

In the case of a conventional FOUP, to deal with the above request, aninlet hole for introducing purging gas into the pod and an outlet holefor discharging the purging gas are formed at the bottom of the FOUP.These inlet and outlet holes are respectively connected with an inlethole and outlet hole for purging gas set on a support pedestal on whichthe pod is mounted. As an actual operation, a high-pressure gascontrolled at a high cleaning degree is introduced into the pod from thesupport pedestal side through these inlet holes. At the same time, thegas and contaminant present in the pod are discharged to the outside ofthe pod through these outlet holes. Contaminant or the like brought intothe pod has been removed in accordance with the operation.

However, only by introducing a high-pressure gas from the bottom of thepod, it is considered that a gas flow mainly passes through a portionnearby the outer periphery of a wafer through which gas easily passes.Therefore, it is considered that it is difficult to pass a gas having asufficient flow rate through the upper and lower faces of individualwafers held by keeping very small intervals. However, contaminant or thelike is mainly attached to the upper face or lower face of a wafer andtherefore, it is considered that it is difficult to sufficiently removecontaminant or the like by a conventional method.

To securely remove the contaminant from a wafer, the method disclosed inJapanese Patent Application Laid-Open No. 2003-45933 is proposed. In thecase of this method, a space for housing an opener is formed separatelyfrom a conveying chamber. The space has a gas supply port at the frontupper portion of the opening of a pod. Clean gas is supplied into thepod from the gas supply port and the clean gas circulating through thepod and discharged to the space from the bottom of the pod is exhaustedfrom the bottom of the space. By using the above configuration andthereby circulating the clean gas through the pod, it is possible tomore securely remove contaminant or the like, compared with the case ofthe conventional method.

Moreover, Japanese Patent Application Laid-Open No. 11-251422 disclosesa method for introducing clean gas between wafers held in a pod. In thecase of this method, a gas introducing channel and a gas dischargingchannel communicating with groove portions for supporting wafers areformed in the pod. By spraying clean gas on the surface of each waferthrough the gas introducing channel and discharging the clean gascontaining contaminant or the like through the gas discharging channel,it is possible to more securely remove the contaminant.

In the case of the method disclosed in Japanese Patent ApplicationLaid-Open No. 2003-45933, an effect can be expected on reduction ofhumidity and of an oxidizing gas in a pad and prevention of organiccontamination to a certain extent. However, it is considered that it isalso difficult to effectively replace the gas present between wafersheld by keeping very small spaces. Therefore, it is considered that itis also difficult to obtain an effect for removing contaminant attachedto the upper and lower faces of a wafer.

According to the method disclosed in Japanese Patent ApplicationLaid-Open No. 11-251422, it is considered that it is possible to removecontaminant attached to upper and lower faces of a wafer. However, it isconsidered that it is difficult to keep the inside diameter of a gasintroducing channel at a large value from the viewpoint of an actualconfiguration. Therefore, a difference occurs in a gas pressuresintroduced on the surface of a wafer or times introduced at apredetermined pressure at the upstream side and downstream side of thechannel and it is considered that the contaminant removal effect dependson a wafer holding position.

Moreover, arrangement of a support pedestal, pod shape, and holes forsupplying and discharging clean gas for purging inside of pod is almoststandardized in the semiconductor manufacturing business circle.Therefore, the pod disclosed in Japanese Patent Application Laid-OpenNo. 11-251422 requiring a configuration different from the standard hasa problem that the pod cannot be shared with a support pedestalgenerally used at present.

DISCLOSURE OF THE INVENTION

The present invention is made in view of the above situation and itsobject is to provide a purging method and a purging apparatus for a FOUPcapable of effectively removing a contaminant or the like attached on awafer.

To solve the above problems, a purging apparatus of the presentinvention is a purging apparatus for applying the purging operation toan object housed in a pod having, a body constituted of an opening and aplurality of shelves on which objects to be housed are arranged in apredetermined direction, and a lid capable of being separated from thebody and closing the opening, by spraying predetermined gas on theobject to be housed, characterized by having a frame capable of movingthe front of the opening in the predetermined direction and a gas supplynozzle movable in a predetermined direction by keeping a predeterminedpositional relation with the frame while the lid is separated from thebody.

In the case of the above purging apparatus, it is also allowed that theframe holds a sensor for mapping the object housed in the pod and thegas supply nozzle is set in parallel with the sensor. Moreover, in thecase of the above purging apparatus, it is also allowed to synchronizethe timing at which the predetermined gas is sprayed from the gas supplynozzle with the timing at which the gas supply nozzle passes through aplane on which the object to be housed extends when the gas supplynozzle moves in the predetermined direction. Furthermore, in the case ofthe above purging apparatus, it is allowed that the gas supply nozzlespouts the predetermined gas in a direction parallel with the plane onwhich the object to be housed extends or a direction facing downward bya predetermined angle from the plane.

Furthermore, in the case of the above purging apparatus, the object tobe housed corresponds to a wafer used for semiconductor fabrication oreach of various products which is treated under a high-cleanenvironment. In the case of the pod, there is a FOUP as an example whichhouses a semiconductor wafer. However, the example is not restricted tothe FOUP as long as it houses various products. Moreover, a state inwhich the lid is separated from the body corresponds to a state in whichthe pod is mounted on a load port and a wafer housed in the pod istransferred to a wafer treating apparatus through the load port.Furthermore, the purging operation described above represents anoperation for removing contaminant such as dust, organic substance,impurity element, or oxidizing gas. Furthermore, mapping represents anoperation for detecting presence or absence of a wafer housed in eachstage of a shelf and relating the wafer to positional information of theshelf.

Furthermore, to solve the above problem, a purging apparatus of thepresent invention is a purging apparatus for applying the purgingoperation to an object housed in a pod having, a body constituted of anopening and a plurality of shelves arranged in a predetermined directionon which objects to be housed are mounted and a lid separable from thebody to close the opening, by spraying predetermined gas on the objectto be housed, characterized by including a gas supply nozzle which isseparated from an end of the object to be housed by a predetermineddistance and almost uniformly sprays the predetermined gas on almost thewhole area of a face extending vertically to the predetermined directionof the objects to be housed and a support member capable of driving thegas supply nozzle in the predetermined direction by supporting the gassupply nozzle.

In the case of the above purging apparatus, it is preferable that thesupport member is a member for setting or removing the lid to or fromthe body portion of the pod. Moreover, it is preferable that the timingat which the predetermined gas is spouted from the gas supply nozzlesynchronizes with the timing at which the support member passes throughthe plane on which the object to be housed extends when the supportmember moves in the predetermined direction. Furthermore, it ispreferable that the gas supply nozzle spouts the predetermined gas to anarea surrounded by a face parallel with a plane on which the object tobe housed extends and a face extending downward by a predetermined anglefrom the plane.

In the case of the above purging apparatus, the object to be housedcorresponds to a wafer used for semiconductor fabrication or eachproduct which is treated under a high-clean environment. Moreover,though the pod is a FOUP as an example for housing a semiconductorwafer, the example is not restricted to the FOUP as long as it housesvarious products. Furthermore, a state in which the lid is separatedfrom the body corresponds to a state in which the pod is mounted on aload port and a wafer housed in the pod is transferred to a wafertreating apparatus through the load port. Furthermore, the above purgingoperation represents an operation for removing contaminant such as dust,organic substance, impurity element, oxidizing gas or the like, presentby attaching to a product or the like. Furthermore, mapping representsan operation for detecting presence or absence of a wafer housed in eachstage of a shelf and relating the wafer to the positional information onthe shelf.

To solve the above problem, a purging method of the present invention isa purging method for applying the purging operation to an object housedin a pod having, a body constituted of an opening and a plurality ofshelves arranged in a predetermined direction on which objects to behoused are mounted, and a lid separable from the body to close theopening, by spraying predetermined gas on the object to be housed,characterized by including a step of separating the lid from the body,and purging the object to be housed by moving a gas supply nozzle alongthe predetermined direction at the front of the opening, and sprayingpredetermined gas on the object to be housed from the gas supply nozzle.

In the case of the above purging method, it is also allowed that the gassupply nozzle is set in parallel with a sensor and a step of performingpurging and a step of mapping an object housed in the pod by the sensorare simultaneously performed. Moreover, in the case of the above purgingmethod, it is also allowed that the step of performing purging isperformed synchronously with the timing at which the gas supply nozzlepasses through a plane on which the object to be housed extends when thegas supply nozzle moves in the predetermined direction. Furthermore, inthe case of the above purging method, at the step of performing purging,it is also allowed that the gas supply nozzle spouts the predeterminedgas in a direction parallel with a plane on which the object to behoused extends or a direction facing downward by a predetermined angle.

In the case of the above purging method, the object to be housedcorresponds to a wafer used for semiconductor fabrication or variousproducts which are treated under a high-clean environment. Moreover, thepod is a FOUP as an example for housing a semiconductor wafer. However,the example is not restricted to the FOUP as long as it houses variousproducts. Moreover, a state in which the lid is separated from the bodycorresponds to a state in which a wafer housed in the pod is transferredto a wafer treating apparatus through a load port. Furthermore, theabove-described purging operation represents an operation for removingcontaminant such as dust, organic substance, impurity element, oxidizinggas or the like present by attaching onto a product. Moreover, mappingrepresents an operation for detecting presence or absence of a waferhoused in each stage of a shelf and relating the wafer to the positionalinformation on the shelf.

Moreover, to solve the above problem, a purging method of the presentinvention is a purging method for applying the purging operation to anobject housed in a pod having a body constituted of an opening and aplurality of shelves arranged in a predetermined direction on whichobjects to be housed are mounted, and a lid separable from the body toclose the opening, by spraying predetermined gas on the object,characterized by including a step of separating the lid from the body, astep of holding a state in which the front of the opening is separatedfrom an end of the object to be housed by a predetermined distance andthereby moving a gas supply nozzle along the predetermined direction,and a step of almost uniformly spraying the predetermined gas on almostthe whole area of a face extending in a direction vertical to the,predetermined direction of the object to be housed by the gas supplynozzle and thereby purging the object to be housed.

In the case of the above purging method, it is preferable that the gassupply nozzle is fixed to a door for setting or removing the lid to orfrom the body of the pod. Moreover, the step of performing purging isperformed synchronously with the timing at which the gas supply nozzlepasses through a plane on which the object to be housed extends when thegas supply nozzle moves in a predetermined direction. Furthermore, inthe step of performing purging, the gas supply nozzle spouts thepredetermined gas between a face parallel with a plane on which theobject to be housed extends and a face extending by facing downward by apredetermined angle from the plane.

In the case of the above purging method, the object to be housedcorresponds to a wafer used for semiconductor fabrication or variousproducts which are treated under a high-clean environment. Moreover, thepod is a FOUP as an example for housing a semiconductor wafer. However,the example is not restricted to the FOUP as long as it houses variousproducts. Moreover, a state in which the pod is separated from the bodycorresponds to a state in which the pod is mounted on a load port and awafer housed in the pod is moved to a wafer treating apparatus throughthe load port. Furthermore, the above-described purging operationrepresents an operation for removing contaminant such as dust, organicsubstance, impurity element, oxidizing gas or the like present byattaching onto a product. Furthermore, mapping represents an operationfor detecting presence or absence of a wafer housed in each stage of ashelf and relating the wafer to the positional information on the shelf.

According to the present invention, it is possible that a gas supplynozzle enters a pod from a pod opening to spray high clean gas on thesurface of a wafer. Moreover, the gas supply nozzle can move in adirection in which wafers are superimposed and individually spray gas oneach wafer. Therefore, it is possible to effectively and securely removecontaminant such as dust or impurity attached to the surface of a wafer.Moreover, it is possible to perform the operation for purging the insideof the pod any time during wafer treatment by using the gas supplynozzle and hold a wafer under a cleaner environment. Furthermore, thepresent invention can be executed for a mapping apparatus of an existingFOUP system by only adding a gas supply nozzle and a gas pipe, and canbe set to a standardized system easily and inexpensively.

Furthermore, according to the present invention, a gas supply nozzle canspray high clean gas on the whole area of the surface of a wafer bykeeping a predetermined distance from the wafer. Furthermore, the gassupply nozzle can move in a direction in which wafers are superimposedand it is possible to individually spray each wafer with gas. Therefore,it is possible to effectively and securely remove contaminant such asdust or impurity attached to the surface of a wafer. Moreover, it ispossible to perform the operation for purging the inside of a pod anytime during wafer treatment by using a gas supply nozzle and hold awafer under a cleaner environment. Furthermore, it is possible toexecute the present invention for the door of a load port of an existingFOUR system by only adding a gas supply nozzle and a gas pipe andinexpensively and easily set the present invention to a standardizedsystem.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing a purging apparatus, a pod, a pod lid,and a part of an opener of first embodiment of the present invention andshowing a schematic configuration of them when viewed from a side;

FIG. 2 is an illustration showing a schematic configuration when viewinga purging apparatus and configuration set to the periphery of the firstembodiment of the present invention from the upper portion;

FIG. 3A is an illustration showing a schematic configuration whencontracting the opener and its nearby configuration and viewing themfrom a side;

FIG. 3B is an illustration showing a schematic configuration whenviewing the configuration shown in FIG. 3A from the conveying chamberside;

FIG. 4A is a front view of a movable portion of an opener of an exampleof the above embodiment viewed from the load port side;

FIG. 4B is an illustration showing the configuration shown in FIG. 3Aviewed from a side;

FIG. 5 is an illustration showing a schematic configuration when viewingan opener and the like showing a mapping sequence of a wafer from a sideand showing a state when the mapping preparation is completed;

FIG. 6 is an illustration sowing a schematic configuration when viewingan opener and the like showing a mapping sequence of a wafer from a sideand showing a state in which the mapping operation is completed;

FIG. 7 is an illustration showing a schematic configuration when viewingan opener and the like showing a mapping sequence of a wafer from a sideand showing a state in which mapping and the opening operation of a lidare all completed;

FIG. 8A is an illustration showing a schematic configuration whenviewing a purging apparatus of second embodiment of the presentinvention, a pod, a lid for the pod, and a part of an opener from aside;

FIG. 8B is a schematic configuration when viewing the purging apparatusof the second embodiment of the present invention, a pod, a the lid forthe pod, and a part of an opener from a side;

FIG. 8C is an illustration showing a schematic configuration of anessential portion of the purging apparatus of the second embodiment ofthe present invention, viewed from a side;

FIG. 9A is an illustration showing a schematic configuration whenviewing the purging apparatus of the second embodiment of the presentinvention and a configuration set at the periphery from above;

FIG. 9B is an illustration showing a schematic configuration whenhorizontally cutting an essential portion of the purging apparatus ofthe second embodiment of the present invention and viewing the crosssection from above;

FIG. 10A is an illustration showing a schematic configuration whencontracting the opener shown in FIGS. 8A to 8C and the configurationnearby the opener and viewing them from a side;.

FIG. 10B is an illustration showing a schematic configuration whenviewing the configuration shown in FIG. 10A from the conveying chamberside;

FIG. 11A is a front view of the movable portion of an opener of anexample relating to the above embodiment viewed from the load port side;

FIG. 11B is an illustration showing the configuration shown in FIG. 11Aviewed from a side;

FIG. 12 is an illustration showing a schematic configuration whenviewing an opener and the like showing the mapping sequence of a waferfrom a side and showing a state in which mapping preparation iscompleted;

FIG. 13 is an illustration sowing a schematic configuration when viewingan opener and the like showing the mapping sequence of a wafer from aside and showing a state in which the mapping operation is completed;

FIG. 14 is an illustration showing a schematic configuration whenviewing an opener and the like showing the mapping sequence of a waferfrom a side and showing a state in which mapping and the openingoperation of a lid are all completed;

FIG. 15 is a general side view showing a schematic configuration of awafer treating apparatus to which the present invention and prior artare applied;

FIG. 16A is an illustration showing a schematic configuration whenenlarging a conventional opener of the apparatus shown in FIG. 15 and aconfiguration nearby the opener and viewing them from a side;

FIG. 16B is an illustration showing a schematic configuration whenviewing the configuration shown in FIG. 16A from the conveying chamberside; and

FIG. 17 is an illustration showing a schematic configuration whenviewing an opener and the like showing the purging operation of a waferfrom a side and showing a state in which purging preparation iscompleted.

BEST MODE FOR CARRYING OUT THE INVENTION FIRST EMBODIMENT

First embodiment of the present invention is described below byreferring to the accompanying drawings.

FIG. 1 shows a schematic configuration of a purging apparatus of thepresent invention, which is an illustration showing the outline whenviewing a pod, a wafer housed in the pod, and a purging apparatus of thepresent invention from a side. FIG. 2 is an illustration showing theoutline of an essential portion when viewing each configuration shown inFIG. 1 and configurations following each configuration from above.Various configurations such as a shelf for supporting a wafer andsealing member set between a lid and a pod and the like are originallyincluded in the pod and various configurations follow a door. However,because these configurations are not directly related to the presentinvention, detailed illustration and description are omitted.

In FIG. 1, a frame 5 constituted of a frame member is set so as tosurround the circumference of a door 6 of an opener. A pair of sticks 13a and 13 b shown in FIG. 2 are set on the frame 5. These sticks 13 a and13 b head for the inside of a pod 2 from the opening face of the pod 2and extend in a direction almost vertical to the opening face. Thesticks 13 a and 13 b support gas supply nozzles 21 a and 21 b so thatthe nozzles 21 a and 21 b head for the direction same as that of thesticks. A not-illustrated gas supply line is connected to each of thegas supply nozzles 21 a and 21 b and thereby, it is possible to supply aclean gas to the nozzles in accordance with an operation from theoutside. These gas supply nozzles 21 a and 21 b are sequentially movedin a direction in which wafers 1 are superimposed to supply a clean gasbetween the wafers 1. As a result, the removal operation of contaminantin the surface and back of a wafer and the inside of the pod 2 by aclean gas, the so-called purging operation is performed.

In the case of this embodiment, the gas supply nozzles 21 a and 21 b areset to a position which becomes an object of the central line of the pod2, that is, the central line of the wafer 1 held in the pod separated bya predetermined interval d. Moreover, the nozzles 21 a and 21 b arefixed to their corresponding sticks 13 a and 13 b so that gas can besupplied by facing in parallel with the surface of the wafer 1 ordownward by a predetermined angle a. It is preferable that theseinterval d and angle a are properly adjusted so that contaminant on thewafer 1 can be more effectively removed and this can be discharged fromthe pod 2 in accordance with the interval between wafers held by the pod2 and the shape of the pod 2. Furthermore, from the same reason it isalso allowed to use a configuration for changing the number of nozzlesby the example concerned or make a nozzle drivable.

In the case of the present invention, it is possible to removecontaminant or the like from each wafer and hold a wafer in a pod at acleaning degree higher than ever. Moreover, in the case of the presentinvention, it is possible to control a gas flow rate and purging timerequired to remove contaminant or the like for each wafer. Therefore, itis also possible to always remove contaminant at a constant conditionand easily keep the control state of every wafer in a pod constant.

It is also allowed to discharge the gas supplied into the pod 2 by thegas supply nozzles 21 a and 21 b by using an exhaust hole which isconventionally set to the pod 2. Moreover, because the purging operationis performed while the lid 4 is opened, it is allowed to perform thepurging operation by using a not-illustrated exhaust system set in theconveying chamber. Furthermore, it is considered that it is preferableto prevent contaminant or the like once removed from a wafer from beingreattached to the inside of a pod or from entering the conveyingchamber. In this case, as shown in the above-described Japanese PatentApplication Laid-Open No. 2003-45933, it is allowed to set a smallchamber dedicated to exhaust communicating with a pod opening in aconveying chamber in order to efficiently exhaust the clean gas used toremove contaminant or the like.

As described above, it is preferable that the contaminant or the likeonce removed from the surface of a wafer is quickly conveyed to theoutside of a pod. Therefore, to more effectively remove contaminant, itis considered to add a port dedicated to exhaust corresponding to eachwafer as shown in the above-described Japanese Patent ApplicationLaid-Open No. 11-251422. However, addition of this configurationrequires a large standard change of a pod corresponding to the standard.Therefore, when using the present invention for a system relating to aFOUP presently used, it is considered that it is preferable not to usethe above exhaust port.

Moreover, a case is considered in which contaminant or the like attachesto a wafer in the form of dust. It is considered that this dust iselectrified and frequently attaches to a wafer due to electrostaticattracting force. In the case of this dust, by spraying ionized gas on awafer instead of high clean gas, it is possible to more efficientlyremove the dust. Therefore, it is more preferable to use a configurationcapable of supplying an ionized gas according to necessity by adding theso-called ionizer for ionizing gas to a gas supply nozzle or nearby thenozzle.

(An Example to which this Embodiment is Applied)

Then, a case of applying a purging apparatus of the present invention toa system relating to a presently-used FOUP is described by referring tothe accompanying drawings. Since, a semiconductor wafer treatingapparatus to which the present invention is applied and a pod whoseschematic configurations are almost the same as the configurationsdescribed for the prior art, description of the same configuration isomitted. A configuration for performing the mapping operation of a waferheld in the pod 2 is frequently added to the opener 3. The configurationincludes a pair of transmission sensors for detecting presence orabsence of a wafer, a frame for supporting the sensors, a mechanism fordriving the frame, a mechanism for detecting the present position of thesensor and the like. In the case of this applied example, the presentinvention can be more easily executed by commonizing the frame 5 forsupporting a gas supply nozzle of the present invention with the framefor supporting the transmission sensors.

In the case of a schematic configuration of the wafer treating apparatus50, a conveying-chamber opening 10 slightly larger than the lid 4 of thepod 2 is formed at the load port portion-51 side in the conveyingchamber 52 as shown in FIG. 8 as the prior art. The opener 3 foropening/closing the lid 4 of the pod 2 is set to the conveying-chamberopening-10 side in the conveying chamber 52. In this case, by referringto FIGS. 3A and 3B, the opener to which the present invention is appliedis described. FIG. 3A is an illustration showing the whole of anapparatus by contracting the portion of the load port portion 51, pod 2,opener 3, and lid 4 in FIG. 1 and FIG. 3B is an illustration whenviewing configuration shown in FIG. 3A from the inside of the conveyingchamber 52.

The opener 3 has the door 6 and frame 5. The door 6 is a plate having asize for closing the conveying-chamber opening 10 and holding portions11 a and 11 b serving as vacuum attraction holes are formed on the faceof the plate. When the door 6 closes the conveying-chamber opening 10, aface located at the pod-2 side is a plane capable of closely contactingwith the lid 4. The fixed member 46 having a hole is set to the door 6.The door 6 is fixed by the fact that a pivot 45 set at the upper end ofthe door arm 42 rotatably passes through the hole. A hole is formed atthe lower end of the door arm 42. The pivot 40 passes through the holeand a hole present at the front end of the rod 37 serving as a part ofthe pneumatic door-opening/closing cylinder 31 serving as adoor-opening/closing drive. Thereby, the door arm 42 is connected withthe cylinder 31 and rotatably supported by the cylinder 31.

The frame 5 is a structure constituted of a frame member set so as tosurround the door 6 along the conveying-chamber opening 10. The frame 5is set to upper ends of frame arms 12 a and 12 b extending on the framemember under the frame 5. A not-illustrated hole is formed at the lowerends of the frame arms 12 a and 12 b. A pivot 44 passes through the holeand a hole at the front end of a rod 38 serving as a part of a pneumaticframe driving cylinder 35 serving as a frame drive. Thereby, these framearms are connected with a cylinder 35 and are rotatably supported by thecylinder 35.

The frame arms 12 a and 12 b are vertically extended symmetrically andin parallel along the central axis of the frame 5. A rod 47 vertical tothe frame arms 12 a and 12 b is set between upper ends and lower ends ofthe frame arms 12 a and 12 b. A fixed member 39 serving as a fulcrumsupport portion vertically extended from the support member 60 is set tothe support member 60. The fixed member 39 has a through-hole parallelwith the support member 60. A bearing (not illustrated) is set to thethrough-hole of the fixed member 39 and the outer ring of the bearing isrotatably supported by the inner wall of the through-hole and the innerring of the bearing rotatably supports the rod 47. Thereby, the rod 47constitutes the fulcrum 41 while it is included in the through-hole ofthe fixed member 39.

The fulcrum 41 is constituted as a fulcrum on the same axis serving asthe fulcrums of the arm frames 12 a and 12 b and the fulcrum of the doorarm in common. That is, another through-hole is formed between the upperend and the lower end of the door arm 42. The fulcrum 41 is constitutedby passing the rod 47 through the through-hole. The door arm 42 canrotate about the fulcrum 41 by the telescopic motion of the rod 37according to driving by the cylinder 31. The fulcrum 41 of the door arm42 is fixed to the support member 60 set to the movable portion 56 whichcan be vertically moved. The door 6 has holding ports 11 a and 11 b andis able to hold the lid 4 of the pod 2 by means of vacuum attraction.The door arm 42 is set so as to be almost vertical while pressing thedoor 6 against the conveying-chamber opening 10 (hereafter referred toas standby state) and the door 6 moved in a direction separate from thewall surface of the conveying chamber 52 by rotating the door arm 42.

The frame arms 12 a and 12 b can rotate about the fulcrum 41 inaccordance with the telescopic motion of the rod 38 in accordance withdriving by the frame driving cylinder 35. That is, the frame arms 12 aand 12 b are also fixed to the support member 60 set to the movableportion 56 which can be vertically moved. The frame 5 is set so as todiagonally separate from the wall surface of the conveying chamber 52when the door 6 is kept in a standby state. That is, under the abovestate, the frame arms 12 a and 12 b are diagonally supported so as tohave a certain angle from the door arm 42 and the upper portion of theframe 5 is separate from the wall surface of the conveying chamber 52 bya certain distance. When the frame 5 rotates the frame arms 12 a and 12b in a direction to be contacted with the wall surface of the conveyingchamber 52, the frame 5 almost contacts with the wall surface of theconveying chamber 52.

Support rods 13 a and 13 b are fixed to a frame member set to the upperportion of the frame 5 so as to protrude toward the wall surface of theconveying chamber 52. Transmission sensors 9 a and 9 b serving as firsttransmission sensors are set to front ends of the support rods 13 a and13 b so as to be faced each other and the gas supply nozzles 21 a and 21b are set so as to satisfy the above positional relation.

The movable portion 56 for vertically moving the opener 3 is set to thesemiconductor-wafer treating apparatus 50. FIG. 4A is an illustrationwhen viewing the movable portion 56 of the opener 3 from the load portportion-51 side and FIG. 4B is an illustration showing the arrow view Xin FIG. 4A. The movable portion 56 includes a pneumatic rod-lesscylinder 33 for vertically moving and the support member 60 and is setbelow the downside of the pod 2 so that the portion 56 is brought to thedownstream side of air flow from the pod 2. The fixed member 39,pneumatic cylinder 31, and cylinder 35 are set to the support member 60.The movable portion 56 is set to the load port portion-51 side andsupports the opener 3 at the conveying chamber-52 side by the door arm42 and frame arms 12 a and 12 b through a long hole 57 formed on acompartment 55.

The long hole 57 is set by using the moving direction of the movableportion 56, that is, the vertical direction in the case of thisembodiment as a longitudinal direction. Moreover, the load port portion51 is comparted from the conveying chamber 52 by a cover 58 so that thecleaning degree in the conveying chamber 52 is not degraded by the longhole 57. Moreover, a limiter 59 for preventing overrun when the opener35 lowers is set below the compartment 55. The rod-less cylinder 33 andguides 61 a and 61 b are set to the compartment 55 along the long hole57. The movable portion 56 is vertically moved by the rod-less cylinder33 along the guides 61 a and 61 b. A sensor dog 7 is set at the side ofthe movable portion 56 along the rod-less cylinder 33.

The sensor dog 7 is a plate extending in the direction along therod-less cylinder 33 and has index means arranged at constant intervalsin its longitudinal direction. This embodiment has a concavo-convexportion 12 serving as cutouts arranged at constant intervals as indexmeans. Then, the number of concaves and convexes corresponds to thenumber of stages of a wafer arrangement shelf in a pod and moreover,concaves and convexes are arranged so that they always correspond to onecutout when coming to an optional shelf having a movable portion. Atransmission sensor 8 serving as a second transmission sensor is fixedon the horizontal compartment 55 at the sensor dog-7 side of the movableportion 56.

The sensor portion of the transmission sensor 8 is set so as to hold theconcavo-convex portion 12 having cutouts at constant intervals set tothe sensor dog 7. The concavo-convex portion 12 of the sensor dog 7 canbe detected in accordance with movement of the movable portion 56. Athird transmission sensor 62 is set to the support member 60 of themovable portion 56 and a limiter 64 is set to the compartment 55 nearbythe lower end of the long hole 57. In the case of the present mechanism,when a protruded portion light-shields the limiter 64 a stop signal isoutput to the movable portion 56 and the whole operation of the opener 3stops.

Then, based on these configurations, how the contaminant removaloperation on the wafer 1 and the mapping operation are performed isdescribed by referring to FIGS. 3A and 3B to FIG. 7. FIG. 3A is anillustration showing a standby state, FIG. 5 is an illustration showinga state in which the frame 5 is operated by opening/closing the lid 4,FIG. 6 is an illustration showing a state in which the contaminantremoval operation of the wafer 1 and the mapping operation arecompleted, and FIG. 7 is an illustration showing a state in which theframe 5 returns to a standby state after an operation applied to thewafer 1 is completed. Moreover, FIGS. 4A and 4B show a front view and aside view on a sensor dog set to detect the driving position of theframe 5 and relevant configuration.

The wafer 1 satisfying the treatment standard of the pretreatment ishoused on a shelf in the pod 2 completing the pretreatment step whilethe wafer 1 not satisfying the standard is excluded from the step at thestage of the pretreatment. A stage on which the wafers 1 is present anda stage on which the wafer 1 is not present are mixed in stages of theshelf in the pod 2. The pod 2 under the above state is mounted on thepedestal 53 on the conveying chamber 52 as shown in FIG. 3A and moves soas to approach to the conveying-chamber opening 10. Under the abovestate, the opener 3 is kept in a standby state. That is, the rod 37 ofthe door opening/closing cylinder 31 is most extended and the door arm42 is kept in a state in which the door arm 42 presses the door 6against the conveying-chamber opening 10 centering around the fulcrum 41to close it.

In the case of this embodiment, under the above state, the arm 42 iskept in a state of vertically standing. However, the rod 38 of the framedriving cylinder 35 is most contracted and the frame arms 12 a and 12 bare kept in a state of the act so as to dissociate the frame 5 from thewall surface of the conveying chamber 52 about the fulcrum 41. That is,in the case of this embodiment, the frame arms 12 a and 12 b arediagonally kept by having a certain angle from the door arm 42.

FIG. 5 shows a state in which the pod 2 approaches the conveying-chamberopening 10 and the door 6 hold the lid 4. When the pod 2 approaches theconveying-chamber opening 10, the lid 4 of the pod 2 adheres to the door6 and holds the lid 4 of the pod 2 through the holding portions 11 a and11 b by means of vacuum attraction. When the door 6 holds the lid 4, thedoor opening/closing cylinder 31 acts to contract the rod 37. Then, thepivot 40 set to an end of the door arm 42 is attracted to the supportbase-60 side and the door arm 42 rotates so as to dissociate the door 6from the mini-environment opening 10 by the fulcrum 41 in accordancewith the principle of lever to release the lid 4 from the pod 2.

After the lid 4 is released, the upper end of the frame 5 enters theposition of the opening 10 and the movable portion 56 slightly lowersdown to a position where the frame arms 12 a and 12 b can rotate. Afterthe movable portion 56 lowers, the frame arm 12 actually starts itsrotation. That is, the rod 38 of the frame driving cylinder 35 extendsand the frame arms 12 a and 12 b rotate until the frame 5 almostcontacts with the circumference of the conveying-chamber opening 10.Then, the gas supply nozzles 21 a and 21 b and the transmission sensors9 a and 9 b set to the upper portion of the frame 5 exit to the outsidefrom the conveying-chamber opening 10 and is inserted into the pod 2. Atthis point of time, the gas supply nozzles 21 a and 21 b are arranged asshown in FIG. 2. Moreover, the first transmission sensors 9 a and 9 barranged in parallel with the gas supply nozzles 21 a and 21 b arearranged so that the wafer 1 is present on the straight line connectingthe sensors 9 a and 9 b to constitute a detection space.

Under the above state, the movable portion 56 vertically moves and atthe same time, the removal operation of contaminant from individualwafer 1 by spraying high clean gas and the mapping operation of thewafer 1 are sequentially executed. That is, the opener 3 is lowered downto the position shown in FIG. 6 by the rod-less cylinder 33. Thetransmission sensors 9 a and 9 b vertically lower to the face of thewafer 1 together with the movable portion 56 and opener 3. When thewafer 1 is present on a stage of the shelf, the wafer 1 intercepts thelight emitted from the transmission sensor 9 a. However, when the wafer1 is missing from a stage of the shelf, the light for the transmissionsensor 9 a is not intercepted. Each sensor is set so that when thetransmission sensor 9 b is intercepted by the wafer 1, the sensor 9 boutputs a non-transmission signal and when the transmission sensor 9 bis not intercepted by the wafer 1, the sensor 9 b outputs a transmissionsignal.

Thereby, it is possible to determine that the wafer 1 is present whenthe non-transmission signal is detected and determine that the wafer 1is missing when the transmission signal is detected. By spraying highclean gas on the wafer 1 at a predetermined pressure for a predeterminedtime by the gas supply nozzles 21 a and 21 b in response to thistransmission signal, it is possible to effectively remove contaminant orthe like from each wafer. In this case, it is allowed to stop sprayingof high clean gas in accordance with a non-transmission signal byconsidering the gas use efficiency. However, it is also allowed tochange gas spraying conditions by considering the change of the gas flowrates on a wafer to be operated because intervals between wafers aredifferent.

The sensor portion of the transmission sensor 8 is set so as to hold theconcavo-convex portion 12 having cutouts at constant intervals set tothe sensor dog 7. Therefore, when the movable portion 56 lowers, thetransmission sensor 8 also lowers to detect the concavo-convex portion12 of the sensor dog 7. In this case, when the transmission sensor 8passes through a concave portion, it outputs a transmission signalwithout being light-shielded and when the sensor 8 passes through aconvex portion, the transmission sensor 8 is light-shielded to output anon-transmission signal. Therefore, by previously setting theconcavo-convex portion 12 of the sensor dog 7 so that the point of timeat which transmission sensors 9 a and 9 b pass through each stage of ashelf in the pod 2 corresponds to the point of time at which thetransmission sensor 8 passes through a concave portion, transmission ornon-transmission signal detected by the transmission sensor 8 shows asignal on a stage of a shelf through which the transmission sensor 9actually passes.

When the transmission sensor 9 a is light-shielded and the transmissionsensor 8 detects a signal corresponding to a stage of a shelf bycomparing the above signal with a detection result of a transmission ornon-transmission signal detected as a result of the fact that thetransmission sensor 9 a performs light-shielding on the wafer 1, it canbe determined that the wafer 1 is present on the shelf stage. However,when the transmission sensor 9 a is not light-shielded at that time, itcan be determined that the wafer 1 is missing on the stage. By changinghigh-clean-gas spraying timings or spraying conditions in accordancewith the above determination, it is possible to more effectively performthe removal operation of contaminant or the like. When the aboveoperation is repeated for every wafer 1 and a support rod reaches themapping completion position of the opener 3, the contaminant removaloperation and mapping operation are completed.

Thereafter, by contracting the rod 38 of the frame opening/closingcylinder 35 again, the frame arms 12 a and 12 b rotate and the frame 5moves so as to get away from the conveying-chamber opening 10. When therod 38 is most contracted, movement of the frame 5 is completed. Then,the movable portion 56 moves down to the lowest point and completes aseries of operations for removing contaminant or the like and performingmapping for the wafer 1 together with release of the lid 4. FIG. 7 showsthe above state.

As described above, in the case of this embodiment, the gas supplynozzles 21 a and 21 b and the transmission sensors 9 a and 9 b are fixedto the same frame 5. Moreover, the frame arms 12 a and 12 b serving asmeans for rotating the frame 5 and frame driving cylinder are used.Because of setting these configurations to the movable portion 56sufficiently separate from the conveying-chamber opening 10, it isunnecessary to set an apparatus for developing a gas supply nozzle andtransmission sensor nearby the wafer 1. Moreover, by using the sensordog 7 and transmission sensor 8, it is possible to easily generate async signal corresponding to a stage of a shelf in the pod 2. Therefore,it is possible to more effectively remove contaminant or the likesimultaneously with the mapping operation of the wafer 1 without using adriving motor for a drive. Thus, by using the sensor dog 7, it ispossible to use a pneumatic cylinder not capable of generating a signalfor mapping of the wafer 1.

Moreover, in the case of this embodiment, the fulcrum of the door arm 42and that of the mapping frame 5 are commonized by the fulcrum 41.However, even if the both fulcrums are brought to separate fulcrums, thesame advantage can be obtained. That is, even if a first fulcrum to beset on the door arm 42 is different from a second fulcrum to be set onthe mapping frame, the same advantage can be obtained. Though themovable portion 56, fulcrum 41, door opening/closing cylinder 31, andmapping-frame driving cylinder 35 are integrated, it is not alwaysnecessary to integrate them in order to obtain an advantage of thepresent invention. As long as these configurations are set to thedownstream side of an air flow for the pod 2, the same advantage can beobtained.

In the case of this embodiment, a gas supply nozzle is fixed on asupport rod in parallel with a wafer mapping sensor in order to applythe present invention without greatly changing a configuration accordingto the standard of a FOUP. However, the present invention is notrestricted to the above case. Specifically, it is also allowed to fixthe gas supply nozzle onto a frame different from the sensor. Moreover,it is allowed to add a driving mechanism to the gas supply nozzle sothat the gas supply nozzle is movable in parallel with a wafer face orrotatable. By using the above configuration, it is possible to entirelypurse the surface of a wafer even if the number of nozzles is small.Furthermore, it is considered that an attached state of contaminant orthe like fluctuates in accordance with a processing performed justbefore. In this case, it is allowed to change the number of gas supplynozzles in view of the attached state or gas consuming state.

Moreover, in the case of this embodiment, the removal operation ofcontaminant or the like is performed only once in accordance with themapping operation. However, the present invention is not restricted tothe above case. It is possible to always perform the removal operationother than the case in which a robot arm in a conveying chamber accessesa wafer in a pod. Therefore, while various treatments are applied to awafer in the treating apparatus, it is also allowed to repeatedly applythe removal operation to a wafer held in the pod.

Furthermore, though this embodiment describes a FOUP as an object, anapplied example of the present invention is not restricted to thesystem. As long as a system is used which has a container for housing aplurality of objects to be held and a conveying chamber for conveyingthe objects to be held by the container to an apparatus for treating theobjects to be held, it is possible to applying a removing apparatus(purging apparatus) of contaminant or the like of the present invention.

SECOND EMBODIMENT

Second embodiment of the present invention is described below byreferring to the accompanying drawings. FIGS. 8A to 8C are illustrationsrelating to a schematic configuration of a purging apparatus of thepresent invention, which are illustrations showing the outline of astate when viewing a pod, a wafer housing in the pod, and the purgingapparatus of the present invention from a side. FIG. 8A shows the timeof starting the purging operation, FIG. 8B shows the middle of thepurging operation, and FIG. 8C shows an enlarged view of an essentialportion of the purging apparatus. Moreover, FIG. 9A is an illustrationshowing an essential portion when viewing the configurations shown inFIGS. 8A to 8C and a configuration following the configurations fromtheir upper potion and FIG. 9B is an illustration when cutting anessential portion of the purging apparatus by a horizontal face andviewing the essential portion from the upper portion. A shelf forsupporting a wafer, sealing member set between a lid and a pod, andvarious configurations are originally included in the pod and variousconfigurations are attached to a door. However, because theseconfigurations do not have a direct relation with the present invention,detailed illustrations and descriptions of them are omitted.

In FIGS. 9A and 9B, a gas supply nozzle 21 capable of discharging cleangas in the direction shown by an arrow is set to the upper portion of adoor 6 of an opener. A not-illustrated gas supply line is connected tothe gas supply nozzle 21 so that clean gas can be supplied to the nozzlein accordance with an operation from the outside. As shown in FIG. 9B,the gas supply nozzle 21 is constituted of an almost-tubular member 22extending in the direction parallel with the surface of a wafer 1 andthe tubular member 22 has an opening 22 a linearly formed in parallelwith the surface of the wafer 1. Clean gas is introduced into thetubular member from a portion not facing the opening 22 a at almost thecentral portion of the tubular member 22. By successively moving the gassupply nozzle 21 in the direction in which the wafers 1 are superimposeto supply clean gas to each wafer. As a result, the removal operation ofcontaminant or the like on the surface and back of a wafer and inside ofthe pod 2 by clean gas, the so-called purging operation is performed.The door 6 is driven in parallel with the direction in which the wafers1 are superimposed. Therefore, by discharging clean gas from the gassupply nozzle 21 when driving the door 6, the purging operation can besuccessively applied to the wafers 1 in the pod 2.

In the case of this embodiment, the center of the tubular member 22 inthe gas supply nozzle 21 is separated from the opening end of the podbody 2 by a predetermined interval. The opening 22 a has a shape inwhich the clean gas discharged from the opening 22 a is diffused in thehorizontal direction as shown in FIG. 9B and diffused in the verticaldirection as shown in FIGS. 8A to 8C. By setting an interval L betweenthe tubular member 22 and the opening of the pod body 2, clean gas issprayed on the whole surface of the wafer 1 in the horizontal directionto remove contaminant or the like. Moreover, the flow rate of gasnormally discharged from a gas supply nozzle is fastest nearby theopening of the nozzle but it quickly lowers as getting away from theopening. Therefore, when supplying gas from a position too close to awafer end, a large flow rate difference occurs between the upstream sideand the downstream side of the gas flow on the surface of a wafer and alarge difference may occur between removal efficiencies of contaminantor the like or the removal efficiency of contaminant or the like may belowered due to an eddy flow generated when an extremely fast gas flowcollides with a wafer end. That is, by setting the interval L, it ispossible to reduce these possibilities and easily form a gas flowflowing on the surface of a wafer at an almost uniform speed anduniformly and efficiently remove contaminant from the surface and backareas of a wafer. Moreover, by using a configuration in which clean gasis discharged to an area turned downward by an angle P from thehorizontal direction in the vertical direction, new clean gas contactswith the surface and back of a wafer at an angle of a certain degree andit is possible to more efficiently remove contaminant or the like. It ispreferable that the interval L and angle β are properly adjusted so thatcontaminant on the wafer 1 is more efficiently removed and it can bedischarged from the inside of the pod 2 in accordance with the size ofand interval of wafers held in the pod 2, and shape of the pod 2.Moreover, from the same reason, it is allowed to use a configuration forchanging the width, length, opening angle, or number of openings 22 a bythe example concerned or a configuration capable of changing directionsof the opening 22 a.

In the case of the present invention, it is possible to removecontaminant or the like from every wafer or the whole area of surfaceand back of a wafer. Therefore, it is possible to hold wafers in a podat a higher cleaning degree than ever. Moreover, in the case of thepresent invention, it is possible to control a gas flow rate and purgingtime required for the removal operation of contaminant or the like foreach wafer. Therefore, it is also possible to perform the removaloperation always under a constant condition and easily keep the controlstate of every wafer in a pod constant.

It is also allowed to discharge gas or the like supplied into the pod 2from the gas supply nozzle 21 by using an exhaust port which isconventionally set to the pod 2. Moreover, because the purging operationis performed in a state in which the lid 4 is opened, it is also allowedto perform the purging operation by using a not-illustrated exhaustsystem set in the conveying chamber. Furthermore, it is considered thatit is preferable to prevent the contaminant or the like once removedfrom reattaching to other wafer or inside of the pod or flowing into theconveying chamber. In this case, as disclosed in the above JapanesePatent Application Laid-Open No. 2003-45933, it is allowed to set asmall chamber dedicated to exhaust communicating with the opening of apod in a conveying chamber in order to efficiently exhaust the clean gasused for the removal operation of contaminant or the like.

As described above, it is preferable that contaminant or the like onceremoved from a wafer is quickly conveyed to the outside of a pod.Therefore, to more efficiently remove contaminant, it is also consideredto add an exhaust port corresponding to each wafer as shown in the aboveJapanese Patent Application Laid-Open No. 11-251422. However, additionof this configuration requires a great standard change of a podcorresponding to a standard. Therefore, when using the present inventionfor a system relating to a presently-used FOUP, it is considered that itis preferable not to use the above exhaust port.

Moreover, a case is considered in which contaminant or the like isattached to wafer in the form of dust. It is considered that this dustis electrified and frequently attached to a wafer due to electrostaticattracting force. It is possible to efficiently remove the above dustnot by spraying high clean gas on a wafer but by spraying ionized gas onthe wafer. Therefore, it is more preferable to use a configurationcapable of supplying ionized gas according to necessity by adding theso-called ionizer for ionizing gas to a gas supply nozzle or a portionnearby the nozzle.

(One Example to which this Embodiment is Applied)

Then, a case in which a purging apparatus of the present invention isapplied to a system relating to a FOUP currently used is described belowby referring to the accompanying drawings. Because the schematicconfiguration of a semiconductor wafer treating apparatus to which thepresent invention is applied and a pod is almost the same as theconfiguration described for the prior art, description of the sameconfiguration is omitted. It is also allowed to support and drive theabove-described gas supply nozzle 21 by a member independent of theabove described door 6. However, in the case of this applied example,the present invention is more easily executed by setting a gas supplynozzle or the like of the present invention to the upper portion of thedoor 6.

In the case of a schematic configuration of the wafer treating apparatus50, the conveying-chamber opening 10 slightly larger than the lid 4 ofthe pod 2 is set to the load port portion-51 side in the conveyingchamber 52. The opener 3 for opening/closing the lid 4 of the pod 2 isset to the conveying-chamber opening-10 side in the conveying chamber52. In this case, the opener 3 to which the present invention is appliedis described by referring to FIGS. 10A and 10B. FIG. 10A is anillustration showing the whole apparatus by contracting the load portportion 51, pod 2, opener 3, and lid 4 in FIG. 1 and FIG. 10B is anillustration when viewing the configuration shown in FIG. 10A from theinside of the conveying chamber 52.

The opener 3 has the door 6 and frame 5. The door 6 is a plate having asize capable of closing the conveying-chamber opening 10 and holdingportions 11 a and 11 b serving as vacuum inlet ports are set to the faceof the door 6. When the door 6 closes the conveying-chamber opening 10,the face located at the pod-2 side is a plane so that it is able toclosely contact with the lid 4. A fixed member 46 having a hole is setto the door 6. A pivot 45 set to the upper end of the door arm 42 isfixed by rotatably passing through the hole. A hole is formed at thelower end of the door arm 42. A pivot 40 passes through the hole and ahole at the front end of the rod 37 serving as a part of the pneumaticdoor opening/closing cylinder 31 which is a door opening/closing drive.Thereby, the door arm 42 is connected with the cylinder 31 and rotatablysupported by the cylinder 31.

The frame 5 is a structure constituted of a frame member set along theconveying-chamber opening 10 so as to surround the door 6. The frame 5is set to the upper ends of the frame arms 12 a and 12 b extending longon the frame member below the frame 5. A not-illustrated hole is formedat the lower ends of the frame arms 12 a and 12 b. The pivot 44 passesthrough the above hole and a hole at the front end of the rod 38 servingas, a part of the pneumatic frame driving cylinder 35 which is a framedrive. Thereby, the frame arms and cylinder 35 are connected and theframe arms are rotatably supported by the cylinder 35.

The frame arms 12 a and 12 b extend toward the vertical directionsymmetrically and in parallel along the central axis of the frame 5 inorder to uniformly support a load. The rod 47 vertical to the frame arms12 a and 12 b is set between the upper ends and lower ends of the framearms 12 a and 12 b. The fixed member 39 serving as a fulcrum supportportion having a shape vertically extended from the support member 60 isset to the support member 60. The fixed member 39 has a through-holeparallel with the support member 60. A bearing (not illustrated) is setto the through-hole of the fixed member 39 and the outer ring of thebearing is supported by the inner wall of the through-hole and the innerring supports the rod 47. Thereby, the rod 47 constitutes the fulcrum 41while it is included in the through-hole of the fixed member 39.

The fulcrum 41 is constituted as a fulcrum on the same axis serving asthe fulcrums of the arm frames 12 a and 12 b and the fulcrum of the doorarm in common. That is, another through-hole is formed between the upperend and the lower end of the door arm 42. The rod 47 passes through thethrough-hole to constitute the fulcrum 41. The door arm 42 can rotateabout the fulcrum 41 in accordance with the telescopic motion of the rod37 due to driving by the cylinder 31. The fulcrum 41 of the door arm 42is fixed to the support member 60 set to the movable portion 56.which isvertically movable. The door 6 has holding ports 11 a and 11 b and isable to hold the lid 4 of the pod 2 through vacuum attraction. The doorarm 42 is set so as to be almost vertical when it presses the door 6against the conveying-chamber opening 10 (hereafter referred to asstandby state) and the door 6 moves in a direction getting away from thewall surface of the conveying chamber 52 by rotating the door arm 42.

The frame arms 12 a and 12 b can rotate about the fulcrum 41 inaccordance with the telescopic motion of the rod 38 through driving bythe frame driving cylinder 35. That is, the frame arms 12 a and 12 b arealso fixed to the support member 60 set to the movable portion 56 whichis able to vertically move. The frame 5 is set so as to diagonally getaway from the wall surface of the conveying chamber 52 when the door 6is kept in a standby state. That is, under the above state, the framearms 12 a and 12 b are diagonally supported so as to have a certainangle from the door arm 42 and the upper portion of the frame 5 isseparated from the wall surface of the conveying chamber 52 by a certaindistance. When the frame 5 rotates the frame arms 12 a and 12 b in adirection contacting with the wall surface of the conveying chamber 52from the standby state, the frame 5 almost contacts with the wallsurface of the conveying chamber 52.

The support rods 13 a and 13 b are fixed to a frame member set to theupper portion of the frame 5 so as to be protruded toward the wallsurface side of the conveying chamber 52. The transmission sensors 9 aand 9 b respectively serving as a first transmission sensor are set tofront ends of the support rods 13 a and 13 b so as to be faced eachother.

The movable portion 56 for vertically moving the opener 3 is set to thesemiconductor-wafer treating apparatus 50. FIG. 11A is an illustrationwhen viewing the movable portion 56 of the opener 3 from the load portportion-51 side and FIG. 11B is an illustration showing the arrow view Xof FIG. 11A. The movable portion 56 includes the pneumatic rod-lesscylinder 33 and support member 60 for vertically moving and is set to aportion below the downside of the pod 2 so as to be the downstream sideof an air flow of the pod 2. The fixed member 39, pneumatic cylinder 31,and cylinder 35 are set to the support member 60. The movable portion 56is set to the load port portion-51 side to support the opener 3 at theconveying chamber-52 side by the door arm 42 and frame arms 12 a and 12b through the long hole 57 formed on the compartment 55.

The long hole 57 is formed by using the moving direction of the movableportion 56, that is, vertical direction in the case of this example as alongitudinal direction. Moreover, the load port portion 51 and conveyingchamber 52 ate comparted by the cover 58 so that the cleaning degree inthe conveying chamber 52 is not deteriorated by the long hole 57.Moreover, the limiter 59 for preventing overrun of the opener 3 when theopener 3 lowers is set below the compartment 55. The rod-less cylinder33 and guides 61 a and 61 b are set along the long holes 57 in thecompartment 55. The movable portion 56 vertically is moved along theguides 61 a and 61 b by the rod-less cylinder 33. The sensor dog 7 isset along the rod-less cylinder 33 at the side of the movable portion56.

The sensor dog 7 is a plate extending in the direction along therod-less cylinder 33 and has index means at certain intervals in itslongitudinal direction. This example has the concavo-convex portion 12serving as cutouts arranged at constant intervals as index means. Thenumber of concaves and convexes corresponds to the number of stages of awafer arrangement shelf in the pod and moreover, the concaves andconvexes are arranged so that one cutout corresponds without fail whenthe movable portion comes to an optional shelf. The transmission sensor8 serving as a second transmission sensor is fixed on the horizontalcompartment 55 of the movable portion 56 at the sensor dog-7 side.

The sensor portion of the transmission sensor 8 is set so as to hold theconcavo-convex portion 12 having cutouts at constant intervals set tothe sensor dog 7 and detect the concavo-convex portion 12 of the sensordog 7 in accordance with movement of the movable portion 56. The thirdtransmission sensor 62 is set to the support member 60 of the movableportion 56 while the limiter 64 is set to the compartment 55 nearby thedownside of the long hole 57. In the case of this mechanism, when theprotruded portion light-shields the limiter 64, a stop signal is outputto the movable portion 56 to stop the whole operation of the opener 3.

Then, based on these configurations, how the contaminant removaloperation and mapping operation on the wafer 1 are performed isdescribed by referring to FIGS. 10A and 10B to FIG. 14. FIG. 10A is anillustration showing a standby state, FIG. 12 is an illustration showinga state in which the frame 5 is operated by opening/closing the lid 4;FIG. 13 is an illustration showing a state in which contaminant removaloperation and mapping operation of the wafer 1 are completed, and FIG.14 is an illustration showing a state in which the frame 5 returns to astandby state after completion of an operation applied to the wafer 1.Moreover, FIGS. 11A and 11B show a front view and a side view of aconfiguration relating to a sensor dog set to detect the drivingposition of the frame 5, respectively.

The wafers 1 satisfying the treatment standard for pretreatment arehoused in a shelf in the pod 2 completing the previous treatment stepwhile the wafers 1 not satisfying the standard is excluded from the stepat the stage of pretreatment. Stages on which the wafers 1 are presentand stages on which no wafer 1 is present are mixed in stages of a shelfin the pod 2. The pod 2 under this state is mounted on the pedestal 53on the conveying chamber 52 as shown in FIG. 10A and moves so as toapproach the conveying-chamber opening 10. Under this state, the opener3 is kept in a standby state. That is, the rod 37 of the dooropening/closing cylinder 31 is most extended and the door arm 42 isclosed by pressing the door 6 against the conveying-chamber opening 10centering around the fulcrum 41.

In the case of this example, the arm 42 vertically stands under thisstate. However, the rod 38 of the frame driving cylinder 35 is mostcontracted and the frame arms 12 a and 12 b are kept in a state ofacting so as to separate the frame 5 from the wall surface of theconveying chamber 52 centering around the fulcrum 41. That is, in thecase of this example, the frame arms 12 a and 12 b become diagonal at acertain angle from the door arm 42.

FIG. 12 shows a state in which the pod 2 approaches theconveying-chamber opening 10 and the door 6 holds the lid 4. When thepod 2 approaches the conveying-chamber opening 10, the lid 4 of the pod2 closely contacts with the door 6 to hold the lid 4 of the pod 2through the holding portions 11 a and 11 b in accordance with vacuumattraction. When the door 6 holds the lid 4, the door opening/closingcylinder 31 operates to contract the rod 37. Then, the pivot 40 set toan end of the door arm 42 is attracted to the support base-60 side andthe door arm 42 rotates by a supporting point 41 so as to dissociate thedoor 6 from the conveying-chamber opening 10 in accordance with theprinciple of lever to release the lid 4 from the pod 2.

After the lid 4 is released, the upper end of the frame 5 enters theposition of the opening 10. The movable portion 56 slightly lowers up toa position where the frame arms 12 a and 12 b can rotate. After theframe arms 12 a and 12 b lower, the frame arm 12 actually starts itsrotation. That is, the rod 38 of the frame driving cylinder 35 extendsand the frame arms 12 a and 12 b rotate until the frame 5 almostcontacts with the circumference of the conveying-chamber opening 10.Then, the transmission sensors 9 a and 9 b set to the upside of theframe 5 exit to the outside from the conveying-chamber opening 10 andare inserted into the pod 2. At this point of time, the gas supplynozzle 21 is located at the position shown in FIG. 8A. Moreover, thefirst transmission sensors 9 a and 9 b constitute a detection spaceformed so that the wafers 1 are present on a straight line connectingthe sensors 9 a and 9 b.

Under this state, movable portion 56 is vertically moved and at the sametime, the contaminant removal operation and mapping operation of thewafer 1 by spraying high clean gas to each wafer 1 are successivelyexecuted. That is, the opener 3 is lowered up to the position shown inFIG. 13 by the rod-less cylinder 33. The transmission sensors 9 a and 9b lower vertically to the face of the wafer 1 together with the movableportion 56 and opener 3. When the wafer 1 is present on a stage of ashelf, it shields the light emitted from the transmission sensor 9 awhile a wafer is missing from a stage of the shelf, the light emittedfrom the transmission sensor 9 a is not shielded. Each sensor is set sothat the transmission sensor 9 b outputs a non-transmission signal whenit is shielded by the wafer 1 and outputs a transmission signal when itis not shielded by the wafer 1.

Thereby, it can be determined that the wafer 1 is present when thenon-transmission signal is detected and it can be determined that thewafer 1 is missing when the transmission signal is detected. It ispossible to effectively perform the removal operation of contaminant orthe like from each wafer by spraying clean gas on the wafer 1 from thegas supply nozzle 21 for a predetermined time at a predeterminedpressure in response to this transmission signal. In this case, it isalso allowed to stop spraying of high clean gas in accordance with thenon-transmission signal by considering the use efficiency of the gas orchange gas spraying conditions by considering that gas flow rates on awafer to be operated are changed because intervals between wafers aredifferent.

The sensor portion of the transmission sensor 8 is set so as to hold theconcavo-convex portion 12 having cutouts at constant intervals set tothe sensor dog 7. Therefore, when the movable portion 56 lowers, thetransmission sensor 8 also lowers to detect the concavo-convex portion12 of the sensor dog 7. In this case, when the transmission sensor 8passes through a concave portion, the transmission sensor 8 is notlight-shielded and it outputs a transmission signal but when thetransmission sensor 8 passes through a convex portion, the transmissionsensor 8 is light-shielded and it outputs a non-transmission signal.Therefore, by previously setting the concavo-convex portion 12 of thesensor dog 7 so that the point of time when the transmission sensors 9 aand 9 b pass through each stage of a shelf in the pod 2 corresponds tothe point of time when the transmission sensor 8 passes through aconcave portion,(a transmission or non-transmission signals detected bythe transmission sensor 8 shows a signal of a stage of a shelf throughwhich the transmission sensor 9 actually passes.

When the transmission sensor 8 detects a signal corresponding to a stageof a shelf and the transmission sensor 9 a is light-shielded bycomparing the above signal with a detection result of a transmission ornon-transmission signal detected as a result of light-shielding of thetransmission sensor 9 a by the wafer 1, it can be determined that thewafer 1 is present on the shelf stage while the transmission sensor 9 ais not light-shielded at that time, it can be determined that the wafer1 is missing from the shelf stage. By changing high-clean-gas sprayingtimings or spraying conditions, it is possible to more effectivelyremove contaminant or the like. When the above operation is repeatedlyapplied to every wafer 1 and a support rod reaches the mappingcompletion position of the opener 3, the removal operation ofcontaminant or the like and mapping operation are completed.

Thereafter, when contracting the rod 38 of the frame opening/closingcylinder 35 again, the frame arms 12 a and 12 b rotate and the frame 5moves so as to get away from the conveying-chamber opening 10. When therod 38 is most contracted, movement of the frame 5 is completed. Then,the movable portion 56 moves down to the lowest point to complete aseries of operations for releasing the lid 4, removing contaminant orthe like to the wafer 1, and performing mapping. The above state is thestate shown in FIG. 14.

As described above, in the case of this example, the gas supply nozzle21 is fixed to the door 6 which moves in parallel with the direction inwhich wafers are superimposed. Therefore, it is possible to alwayssupply clean gas to each wafer in the same condition. Moreover, by usingthe sensor dog 7 and transmission sensor 8, it is possible to easilygenerate a sync signal corresponding to a stage of a shelf in the pod 2.Therefore, it is possible to more effectively remove contaminant or thelike simultaneously with the mapping operation of the wafer 1 withoutusing a drive motor as a drive.

In the case of this example, the fulcrum of the door arm 42 and that ofthe mapping frame 5 are commonized by the fulcrum 41. However, the sameadvantage can be obtained even if using the both fulcrums as separatefulcrums. That is, the same advantage can be obtained even if usingdifferent fulcrums as a first fulcrum to be set on the door arm 42 and asecond fulcrum to be set on a mapping frame. Though the movable portion56, fulcrum 41, door opening/closing cylinder 31, and mapping-framedriving cylinder 35 are integrated, it is not always necessary tointegrate them in order to obtain the advantage of the presentinvention. As long as these configurations are arranged at thedownstream side of an air flow for the pod 2, the same advantage can beobtained.

In the case of this example, a gas supply nozzle is fixed to the upperportion of a door in order to apply the present invention withoutgreatly changing a configuration according to the standard of FOUP.However, the present invention is not restricted to the above case.Specifically, it is also allowed to fix a gas supply nozzle to adifferent frame constituted of a door. Moreover, it is allowed to add adriving mechanism to a gas supply nozzle so that the gas supply nozzlecan rotate about an axis parallel with a wafer face. Furthermore, it isconsidered that an attached state of contaminant or the like fluctuatesin accordance with a processing performed immediately before. In thiscase, it is allowed to change the width, length, or angle of an openingof a gas supply nozzle or the number of openings in view of the attachedstate and use condition of gas. In this case, increase of the number ofopenings represents increase of the number of openings in the horizontaldirection and increase of the number of openings in the verticaldirection.

Moreover, in the case of this example, the removal operation ofcontaminant or the like is performed only once in accordance with themapping operation. However, the present invention is not restricted tothe above case. It is possible to always perform the removal operationexcept the case in which a robot arm in a conveying chamber accesses awafer in a pod. Therefore, while various treatments are applied to awafer in a treating apparatus, it is allowed to repeatedly apply theremoval operation to a wafer held in a pod.

Furthermore, in the case of this example, a FOUP is described. However,an applied example of the present invention is not restricted to thesystem. As long as a system is used which includes a container forhousing a plurality of objects to be held therein and a conveyingchamber for conveying an object to be held from the container to anapparatus for treating the object to be held, it is possible to apply aremoving apparatus (purging apparatus) of contaminant or the like of thepresent invention to the system.

1. A purging apparatus for purging objects housed in a pod including, abody including an opening and a plurality of shelves arranged in apredetermined direction on which the objects to be housed are mounted,and a lid configured to be removed from the body and to close theopening, the purging apparatus purging the objects by spraying apredetermined gas on the objects to be housed, comprising: a frameconfigured to move relative to the front of the opening in thepredetermined direction while the lid is separated from the body; a doorconfigured to hold the lid, to separate the lid from the body, and tocouple the lid to the body by moving independently from and relative tothe movement of the frame; and a gas supply nozzle movable in thepredetermined direction by keeping a predetermined positional relationwith the frame, wherein the frame holds a sensor for mapping the objecthoused in the pod, and the frame inserts the gas supply nozzle into thebody of the pod when the door separates the lid from the body.
 2. Thepurging apparatus according to claim 1, wherein the gas supply nozzle isset in parallel with the sensor.
 3. The purging apparatus according toclaim 1, wherein the timing at which the predetermined gas is spoutedfrom the gas supply nozzle synchronizes with the timing at which the gassupply nozzle passes through a plane on which the object to be housedextends when moving in the predetermined direction.
 4. The purgingapparatus according to claim 1, wherein the gas supply nozzle spouts thepredetermined gas in a direction parallel with the plane on which theobjects to be housed extend or a direction facing downward by apredetermined angle from the plane.
 5. The purging apparatus accordingto claim 1, wherein the objects to be housed are wafers used forsemiconductor fabrication and the state in which the lid is separatedfrom the body is the state in which the pod is mounted on a load portand the wafers housed in the pod are transferred to a wafer treatingapparatus through the load port.
 6. A purging apparatus for purging anobject housed in a pod including, a body including an opening and aplurality of shelves arranged in a predetermined direction on whichobjects to be housed are arranged, and a lid configured to be separatedfrom the body and to close the opening, the purging apparatus purgingthe objects by spraying a predetermined gas on the objects to be housed,comprising: a gas supply nozzle separated from ends of the objects to behoused by a predetermined distance and configured to spray thepredetermined gas on an area of a face extending vertically to thepredetermined direction of the objects to be housed; and a supportmember that supports the gas supply nozzle and is configured to drivethe gas supply nozzle in the predetermined direction; a sensor movablein the predetermined direction with the support member, the sensordetecting a timing at which the support member passes through a plane onwhich each of the objects to be housed extends when the support membermoves in the predetermined direction, wherein the support member is amember for setting or removing the lid to or from the body portion ofthe pod, and the gas supply nozzle sprays the predetermined gas on theobject while the support member holds the lid, and the gas supply nozzlesprays the predetermined gas onto the plane in synchronization with thetiming.
 7. The purging apparatus according to claim 6, wherein the gassupply nozzle spouts the predetermined gas to an area surrounded by aface parallel with a plane on which the objects to be housed extend anda face extended by facing downward by a predetermined angle from theplane.
 8. The purging apparatus according to claim 6, wherein theobjects to be housed are wafers used for semiconductor fabrication andthe state in which the lid is separated from the body is the state inwhich the pod is mounted on a load port and the wafers housed in the podare transferred to a wafer treating apparatus through the load port. 9.A purging method for purging objects housed in a pod including, a bodyincluding an opening and a plurality of shelves arranged in apredetermined direction on which the objects to be housed are mounted,and a lid removable from the body and configured to close the opening,the purging method purging the objects by spraying a predetermined gasto the objects to be housed, comprising: a step of separating the lidfrom the body via a door which is configured to hold the lid, toseparate the lid from the body, and to set the lid to the body; a stepof moving a gas supply nozzle along the predetermined direction at thefront of the opening independently from and relative to movement of thedoor, after the door removes the lid from the body; and a step ofpurging the objects to be housed by spraying the predetermined gas onthe objects to be housed from the gas supply nozzle, wherein the gassupply nozzle is set in parallel with the sensor, and after removing alid, a step of mapping the object by the sensor is performedsimultaneously with the step of performing purging in a state in whichthe gas nozzle is inserted into the body.
 10. The purging methodaccording to claim 9, wherein the step of performing the purging isperformed synchronously with the timing at which the gas supply nozzlepasses through the plane on which the objects to be housed extend whenmoving in the predetermined direction.
 11. The purging method accordingto claim 9, wherein in the step of performing the purging, the gassupply nozzle spouts the predetermined gas in a direction parallel withthe plane on which the objects to be housed extend or a direction facingdownward by a predetermined angle from the plane.
 12. The purging methodaccording to claim 9, wherein the objects to be housed are wafers usedfor semiconductor fabrication and the state in which the lid isseparated from the body is the state in which the pod is mounted on aload port and the wafers housed in the pod are transferred to a wafertreating apparatus through the load port.
 13. A purging method forpurging objects housed in a pod including, a body including an openingand a plurality of shelves arranged in a predetermined direction onwhich the objects to be housed are mounted, and a lid removable from thebody and configured to close the opening, the purging method purging theobjects by spraying a predetermined gas to the objects to be housed,comprising: a step of separating the lid from the body; a step ofholding a state in which the front of the opening is separated from endsof the objects to be housed by a predetermined distance and moving a gassupply nozzle in the predetermined direction; and a step of purging theobject to be housed by spraying the predetermined gas on an area of aface extending in a direction vertical to the predetermined direction ofthe objects to be housed, wherein the gas supply nozzle is fixed to adoor used to set or remove the lid to or from the body of the pod, andafter separating the lid from the body by the door, the gas is sprayedonto each of objects subsequently in accordance with the movement of thedoor, and the step of purging includes a step of detecting, via asensor, a timing at which the gas supply nozzle passes through a planeon which each of the objects to be housed extends when the gas supplynozzle moves in the predetermined direction, and a step of spraying thepredetermined gas from the gas supply nozzle onto the plane respectivelyin synchronization with the detected timing.
 14. The purging methodaccording to claim 13, wherein in the step of purging, the gas supplynozzle spouts the predetermined gas between a face parallel with a planeon which the objects to be housed extend and face extended by facingdownward by a predetermined angle from the plane.
 15. The purging methodaccording to claim 13, wherein the objects to be housed are wafers usedfor semiconductor fabrication and the state in which the lid isseparated from the body is the state in which the pod is mounted on aload port and the wafers housed in the pod are transferred to a wafertreating apparatus through the load port.